When they had measured the attic they had to get a pencil and do a sum. They both got different answers to it at first, and even when they agreed I am not sure they got it right. They were in a hurry to start on the exploration.

"We mustn't make a sound," said Polly as they climbed in again behind the cistern. Because it was such an important occasion they took a candle each (Polly had a good store of them in her cave).

It was very dark and dusty and draughty and they stepped from rafter to rafter without a word except when they whispered to one another, "We're opposite your attic now" or "this must be halfway through our house". And neither of them stumbled and the candles didn't go out, and at last they came where they could see a little door in the brick wall on their right. There was no bolt or handle on this side of it, of course, for the door had been made for getting in, not for getting out; but there was a catch (as there often is on the inside of a cupboard door) which they felt sure they would be able to turn.

"Shall I?" said Digory.

"I'm game if you are," said Polly, just as she had said before. Both felt that it was becoming very serious, but neither would draw back. Digory pushed round the catch with some difficultly. The door swung open and the sudden daylight made them blink. Then, with a great shock, they saw that they were looking, not into a deserted attic, but into a furnished room. But it seemed empty enough. It was dead silent. Polly's curiosity got the better of her. She blew out her candle and stepped out into the strange room, making no more noise than a mouse.

It was shaped, of course, like an attic, but furnished as a sitting-room. Every bit of the walls was lined with shelves and every bit of the shelves was full of books. A fire was burning in the grate (you remember that it was a very cold wet summer that year) and in front of the fire-place with its back towards them was a high-backed armchair. Between the chair and Polly, and filling most of the middle of the room, was a big table piled with all sorts of things printed books, and books of the sort you write in, and ink bottles and pens and sealing-wax and a microscope. But what she noticed first was a bright red wooden tray with a number of rings on it. They were in pairs - a yellow one and a green one together, then a little space, and then another yellow one and another green one. They were no bigger than ordinary rings, and no one could help noticing them because they were so bright. They were the most beautiful shiny little things you can imagine. If Polly had been a very little younger she would have wanted to put one in her mouth.

The room was so quiet that you noticed the ticking of the clock at once. And yet, as she now found, it was not absolutely quiet either. There was a faint - a very, very faint - humming sound. If Hoovers had been invented in those days Polly would have thought it was the sound of a Hoover being worked a long way off - several rooms away and several floors below. But it was a nicer sound than that, a more musical tone: only so faint that you could hardly hear it.

"It's alright; there's no one here," said Polly over her shoulder to Digory. She was speaking above a whisper now. And Digory came out, blinking and looking extremely dirty - as indeed Polly was too.

"This is no good," he said. "It's not an empty house at all. We'd better bunk before anyone comes."

"What do you think those are?" said Polly, pointing at the coloured rings.'

"Oh come on," said Digory. "The sooner-"

He never finished what he was going to say for at that moment something happened. The high-backed chair in front of the fire moved suddenly and there rose up out of it - like a pantomime demon coming up out of a trapdoor the alarming form of Uncle Andrew. They were not in the empty house at all; they were in Digory's house and in the forbidden study! Both children said "O-o-oh" and realized their terrible mistake. They felt they ought to have known all along that they hadn't gone nearly far enough.

Uncle Andrew was tall and very thin. He had a long clean-shaven face with a sharply-pointed nose and extremely bright eyes and a great tousled mop of grey hair.

Digory was quite speechless, for Uncle Andrew looked a thousand times more alarming than he had ever looked before. Polly was not so frightened yet; but she soon was. For the very first thing Uncle Andrew did was to walk across to the door of the room, shut it, and turn the key in the lock. Then he turned round, fixed the children with his bright eyes, and smiled, showing all his teeth.

"There!" he said. "Now my fool of a sister can't get at you!"

It was dreadfully unlike anything a grown-up would be expected to do. Polly's heart came into her mouth, and she and Digory started backing towards the little door they had come in by. Uncle Andrew was too quick for them. He got behind them and shut that door too and stood in front of it. Then he rubbed his hands and made his knuckles crack. He had very long, beautifully white, fingers.

"I am delighted to see you," he said. "Two children are just what I wanted."

"Please, Mr Ketterley," said Polly. "It's nearly my dinner time and I've got to go home. Will you let us out, please?"

"Not just yet," said Uncle Andrew. "This is too good an opportunity to miss. I wanted two children. You see, I'm in the middle of a great experiment. I've tried it on a guinea-pig and it seemed to work. But then a guinea-pig can't tell you anything. And you can't explain to it how to come back."

"Look here, Uncle Andrew," said Digory, "it really is dinner time and they'll be looking for us in a moment. You must let us out."

"Must?" said Uncle Andrew.

Digory and Polly glanced at one another. They dared not say anything, but the glances meant "Isn't this dreadful?" and "We must humour him."

"If you let us go for our dinner now," said Polly, "we could come back after dinner."

"Ah, but how do I know that you would?" said Uncle Andrew with a cunning smile. Then he seemed to change his mind.

"Well, well," he said, "if you really must go, I suppose you must. I can't expect two youngsters like you to find it much fun talking to an old buffer like me." He sighed and went on. "You've no idea how lonely I sometimes am. But no matter. Go to your dinner. But I must give you a present before you go. It's not every day that I see a little girl in my dingy old study; especially, if I may say so, such a very attractive young lady as yourself."

Polly began to think he might not really be mad after all.

"Wouldn't you like a ring, my dear?" said Uncle Andrew to Polly.

"Do you mean one of those yellow or green ones?" said Polly. "How lovely!"

"Not a green one," said Uncle Andrew. "I'm afraid I can't give the green ones away. But I'd be delighted to give you any of the yellow ones: with my love. Come and try one on."

Polly had now quite got over her fright and felt sure that the old gentleman was not mad; and there was certainly something strangely attractive about those bright rings. She moved over to the tray.

"Why! I declare," she said. "That humming noise gets louder here. It's almost as if the rings were making it."

"What a funny fancy, my dear," said Uncle Andrew with a laugh. It sounded a very natural laugh, but Digory had seen an eager, almost a greedy, look on his face.

"Polly! Don't be a fool!" he shouted. "Don't touch them."

It was too late. Exactly as he spoke, Polly's hand went out to touch one of the rings. And immediately, without a flash or a noise or a warning of any sort, there was no Polly. Digory and his Uncle were alone in the room.

CHAPTER TWO

DIGORY AND HIS UNCLE

IT was so sudden, and so horribly unlike anything that had ever happened to Digory even in a nightmare, that he let out a scream. Instantly Uncle Andrew's hand was over his mouth. "None of that!" he hissed in Digory's ear. "If you start making a noise your Mother'll hear it. And you know what a fright might do to her."

As Digory said afterwards, the horrible meanness of getting at a chap in that way, almost made him sick. But of course he didn't scream again.

"That's better," said Uncle Andrew. "Perhaps you couldn't help it. It is a shock when you first see someone vanish. Why, it gave even me a turn when the guinea-pig did it the other night."

"Was that when you yelled?" asked Digory.

"Oh, you heard that, did you? I hope you haven't been spying on me?"